Analytical test apparatus



Sept. 8, 1959 Filed June 8, 1956 Ila.

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ATTORNEY Sept. 8, 1959 w. SAYERS I ET AL ANALYTICAL TEST APPARATUS 3Sheets-Sheet 2 Fi led June a, 1956 Sept. 8, 1959 w. SAYERS ETALANALYTICAL TEST APPARATUS I5 Sheets-Sheet 3 Filed June 8, 1956 FIG.

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INVENTORS WINSTON SA YE RS BY DON .J. WANGELIN gM/MA ATTORNEY UnitedStates Patent ANALYTICAL TEST APPARATUS Winston Sayers, Libertyville,and Don J. Wangelin, Barrington, Ill., assignors to The Pure OilCompany, Chlcago, 111., a corporation of Ohio Application June 8, 1956,Serial No. 590,215

Claims. (Cl. 73-53) This invention relates to an apparatus fordetermining the aniline point and mixed aniline point of petroleumproducts and hydrocarbon solvents.

Because of the variety of applications for petroleum products it becomesnecessary to employ qualitative or semi-quantitative analyticaltechniques to evaluate the adaptability of a petroleum product for aparticular use. Petroleum fractions having the same or similar boilingranges will vary in hydrocarbon composition depending upon the source ofthe crude petroleum oil from which the fractions were obtained. Thepeculiar properties attributable to the various series of hydrocarbonssuch as parafiins, olefins, naphthenes, and aromatics, require that testprocedures be established for qualitatively and semi-quantitativelydetermining the content of these hydrocarbon series in various petroleumproducts. For example, aromatic hydrocarbons have superior solvencyproperties, but when present in distillates such as fuel oil, kerosine,diesel fuel, and the like, they tend to cause these products to burnwith a smoky flame. To determine the presence of aromatic hydrocarbonsin petroleum products there has been established the so-called anilinepoint test (ASTM Designation: D611-55T). According to this test:

Specified volumes of aniline and sample, or aniline and sample plusdiluent, are placed in a tube and mixed mechanically. The mixture isheated at a controlled rate until the two phases become miscible. Themixture is then cooled at a controlled rate and the temperature at whichthe two phases separate is recorded as the aniline point or mixedaniline point.

To effect proper agitation of the test mixture, a specific stirrerdesign is used. This stirrer is fabricated from a length of #14 B and Sgage soft iron Wire. At one end is formed perpendicularly to the shanksection, a ring having a diameter of about 19 mm. The shank section isapproximately 200 mm. long, terminating in a right angle bend to providea handle for manual manipulation of the stirrer.

The test specifications permit the use of any suitable mechanical devicefor operating the stirrer.

It is therefore an object of this invention to provide an apparatus foraniline point test which employs an effective mechanical stirrer,thereby permitting the aniline point test to be carried out in a facilemanner with exccllent repeatability and reproducibility. It is anotherobject of this invention to permit the simultaneous determination of theaniline points of a plurality of samples.

These and other objects of this invention will become apparent from thefollowing detailed description of this invention.

Figure 1 is an isometric sketch of the unitary assembly in an operatingcondition.

Figure 2 is a front view of the stirrer assembly of the apparatusremoved from the panel.

Figure .3 is a side view of the panel assembly.

" Figures 4 and 5 are bottom and rear views, respec- "2 tively, of thecross-bar element to which the stirrer elements are affixed.

Figures 6 and 7 are front and side views, respectively, of the drivewhich operates the cross-bar element.

Figure 8 is a sketch of an alternative assembly employing a tubularstandard.

With reference to the drawing, it is seen that the assembly is mountedon a suitable standard such as panel 10. This standard is provided withsupport means, e.g., panel legs 11a and 11b, which retain it in anupright position. Mounted on the standard at an elevated position iselectric motor 12 which can be retained in position by a platform or thelike, such as motor mounting bracket 13. Attached to the rotating shaft14 of motor 12 is cam-drive 15. Eccentrically positioned on the face ofthe drive is cam 16 which registers with cam groove 17 provided in theface of cam-follower crossarm 18. It is to be noted that thespecifications of the aniline point test, cited supra, advise that a2-inch stroke be employed in stirring the sample. Accordingly, cam 16 ismounted on the face of cam drive 15 at a radius selected to provide astroke of about /3 to 2% inches for the stirrer element.

Guide-rod 19 is attached to cross-bar 18 in fixed relation therewith.This fixed relationship can be retained by employing a means, such asset-screw 25 as illustrated, which will permit periodic adjustments, orby a more permanent technique, e.g., welding, brazing, or the like. Thepath of guide-rod 19 is controlled by guides 26 and 27 which are mountedon upright standard 10 in a manner such that a vertical reciprocatingmotion is given to cross-arm 18. The cross-arm 18 is provided with aplurality of fastening means, such as threaded fasteners 30a and 30b,for attaching stirrer elements 311: and 31b thereto. It is preferredthat a pivotal connection between the stirrer element and the cross-armbe employed; however, a rigid mounting can be used, if desired. Toposition the sample so that it can be effectively stirred, clamps 32aand 32b are provided. It is preferred that these clamps be laterallyadjustable. This can be effected by means of threaded arms 33a and 33bin cooperation with threaded fastener 34a and locking means 35a. Thearms of clamps 32a and 32b grasp sample holders 37a and 37b. Thesesample holders, in accordance with the provisions of the aniline pointtest, cited supra, comprises jacketed test tubes. The test tube isapproximately 25 mm. in diameter and mm. in length, and the jacket isapproximately 37 to 42 mm. in diameter and mm. in length, both beingmade of heat-resistant glass. The sample holders 37a and 37b can befabricated from separate units which are held in spaced relationship bya suitable annular closure such as cork or rubber stopper, or in theform of a unitary element by appropriately welding the lips of thejacket and test tube to a web portion which holds the respective unitsin the required coaxial relationship as shown. This eliminates thenecessity for the annular sealing cork and provides an easily handledand cleanable assembly. For accurate, reproducible results,contamination must be avoided as far as possible, and elimination of thecork ring-seal reduces the chances for any contamination of thematerials under test. To aid in control of heating and cooling rates,the jacketed tube is provided'with inlet 41a and outlet 41b throughwhich a heat exchange medium, such as heated or cooled air, or other gasor liquid, may be introduced and withdrawn at any desired rate toprovide complete control over the critical heating and cooling rates.The mouths of the test tubes are covered with closure means 42a and 42bin which are disposed first openings for ASTM aniline point thermometers43a and 43b and second openings in which are placed short sleeves 44aand 44b which function-as 3 guides for the stirrers. When a stirrerelement is fitted in place, the ring section of the stirrercircumscribes the thermometer.

Although several procedures are available for deter- .colored samples,not darker than No. 8 ASTM color (ASTM Method 13-155) Inemploying theinstant invent-ion for determining aniline point or mixed aniline point,10 ml. of aniline and 10 ml. of a dried sample of petroleum product areplaced in sample holder 37a or 37b. The stirrer element and thermometerare properly arranged in the tube, and closure 42 is fitted in the mouthof the test tube. The thermometer is centered in the sample holder sothat the immersion mark is at the liquid level, making sure that thebulb does not touch the side of the tube. The stirrers 31 are thenattached to threaded fasteners 30 on cross-arm 18. Air lines 53a and5311 are connected to the inlets of the test vessel air jackets, and theair flow is adjusted to a desired rate. Suitable heating means such asburners 50a and Stlb are then started, and motor 12 is energized bypower from a suitable source controlled by switch 54. The motor, 12,cooperating with drive-wheel 15 and cross-arm 18, moves stirirer element31 in reciprocating, uniform, vertical paths within the aniline-samplemixture. The heaters, 50a and are adjusted to give the desired rate oftemperature rise and, when complete miscibility has been attained, theyare turned off and the mixture is allowed porting the various elementsof this invention. Such an expedient is shown in Figure 8. The motorwhich was employed in the preferred embodiment was a 140 rpm, 110 volt,60 cycle motor; however, other types of fixed or variable speed motorscan be employed. It may also be preferred to substitute a crank arm forthe disc-like cam drive employed in the preferred embodiment. Regardlessof the configuration of the cam-drive, counterweight 52 should bemounted on the drive opposite the cam to minimize vibration of theapparatus during its operation. Friction between the cam and cam groovecan also be reduced by employing a rotatable element, such as a ball orroller bearing, as cam element 16. The cross-arm 18 is also susceptibleto variations in design. While the illustrated design shows provisionsfor carrying out two determinations simultaneously, the length of thecross-arm can be varied to permit additional samples to be tested. Inaddition, the positioning and number or" the guide means for controllingthe reciprocative motion of the cross-arm can be altered. For example, asingle guide can be used, the guide means can be mounted above or belowthe cross-arm in place of the upper and lower mounting used in thepreferred embodiment, etc. Normally, cross-arm 18 will be mounted atright angles to guide-rod 19. This does not preclude a non-pe1pendicularjoining of the guide-rod and cross-arm, but in this instance it will benecessary to adjust the positioning of the specimen holder to providefor a uniform length of stroke of each stirrer element employed. It ispreferred that substantially vertical and horizontal relationship bemaintained in constructing and assembling the apparatus of thisinvention. Should deviations in design be considered necessary, thefollowing criteria must be employed.

(a) Positioning of cam on cam-drive to provide a stirrer stroke of 1 to3% inches. This can be made to permit adjustment of the stroke asopposed to the fixed stroke illustrated.

(b) Maintaining parallel relationship between the longitudinal axes ofthe guide ll'Od, sample holder and stirrer path.

(0) Conformance with apparatus requirements of aniline point test methodI (ASTM D-6ll).

Although the foregoing description of this invention is directed to amultiple stirrer apparatus for use in conducting the aniline point test,it is apparent that it will have other analytical applications such asfreezing point determinations, or the like which require a gentle,uniform agitation while carrying out the test work. In theseapplications, various stirrer designs can be used. Accordingly, we claimas our invention:

1. For determining the aniline point in accordance with method I, ASTMdesignation D6l155T, of petroleum products, an apparatus which comprisesan upright standard, an electrical motor mounted on said standard, acam-drive rotated by said motor, a cam eccentrically mounted on saidcam-drive, a cross-arm reciprocatively mounted on said standard, saidcross-arm having a guide rod transversely attached thereto and alongitudinal groove registering with said cam, guide means mounted onsaid standard and slidably engaging said guide rod to maintain auniform, straight line, reciprocative motion for said cross-arm, aplurality of sample holders each comprising a jacketed test tube havingan inlet means and an outlet means in the jacket section, means forclamping said sample holders to said standard, a stirrer element fittedin each of said sample holders, each of said stirrers comprising a shankportion, a ring section extending at a right angle to said shank portionat the terminal end disposed in said sample holder, the other terminalend of said stirrer being afiixed to said reciprocatively mountedcross-arm spaced from said guide rod, the longitudinal axis of saidsample holders and the reciprocative path of the stirrer elementsmounted therein being substantially coextensive, an ASTM aniline pointthermometer disposed in said sample holder, said thermometer beingcircumscribed by the ring section of said stirrer element, and a closuremeans for said sample holder, said closure means having a first openingfor retaining said thermometer in said sample holder, and a secondopening having fitted therein a guide means cooperating with the shankportion of said stirrer element.

2. For determining the aniline point in accordance with method I, ASTMdesignation D-6l1-65-T of petroleum products, an apparatus whichcomprises an upright panel contmning an opening, an electrical motormounted on said panel adjacent said opening, a camdrive rotated by saidmotordisposed within said opening, the plane of rotation of saidcam-drive being substantially coplanar with the plane of said panel, acam eccentrically mounted on said cam-drive, a cross-arm reciprocativelymounted on said panel, said cross-arm having a guide rod transverselyattached thereto and a longitudinal groove registering with said cam,guide means mounted on said panel and slidably engaging said guide rodto maintain a uniform, straight line, reciprocative motion for saidcross arm, said guide means comprising pillow blocks, a plurality ofsample holders, each comprising a jacketed test tube having inlet andoutlet means in the jacket section, means for clamping said sampleholders to said panel, a stirrer element fitted in each of said sampleholders, each of said stirrers comprising a shank portion, a ringsection extending at a right angle of said shank portion at the terminalend disposed in said sample holder, the other terminal end of saidstirrer being afiixed to said reciprocatively mounted cross-armsp-acedfrom said guide rod, the longitudinal axis of said sample holders andthe stirrer elements mounted therein being substantially coextensive, anASTM aniline point thermometer disposed in each of said sample holders,said thermometer being circumscribed by the ring section of said stirrerelement, and a closure means for said sample holder having a firstopening for retaining said thermometer in said sample holder, and asecond opening having fitted therein a guide means for cooperating withthe shank portion of said stirrer element.

3. For determining the aniline point inaccordance with method I, ASTMdesignation D-611-55-T of petroleum products, an apparatus whichcomprises a vertically upright panel containing a circular openingsymmetrical about the vertical axis of said panel, an electrical motorhaving a rotatable shaft mounted on said panel, the axis of said shaftbeing substantially perpendicular to the center of said opening, adisc-like, counter balanced, camdnive disposed within the said openingand rotated by said shaft, a cam eccentrically mounted on the face ofsaid drive cam, the face of said drive cam and the face of said panelbeing substantially coplanar, a horizontal cross-arm reciprocativelymounted on said panel, said cross-aim having a guide rod perpendicularlyand sym metrically attached thereto adjacent the vertical axis of saidcross-arm and in one vertical face thereof, a longitudinal grooveregistering with said cam guide, means comprising pillow blocks mountedon said panel in alignment with the vertical axis thereof and slidablyengaging said guide-rod to maintain a uniform, vertical, straightlinereeiprocative motion, a plurality of sample holders each comprising ajacketed test tube having inlet and outlet means in the jacket portion,means for clamping each of said sample holders to said panel, a stirrerelement fitted in each of said sample holders, each of said stirrerscomprising a shank portion, a ring section extending in a right angle tosaid shank portion at the terminal end of said sample holder, the otherterminal end of said stirrer being afiixed to said reciprocativelymounted cross-arm and spaced from said guide rod, an ASTM aniline pointthermometer disposed in each of said sample holders, said thermometersbeing circumscribed by the ring section of said stirrer element, and aclosure means for each of said sample holders, said closure means havinga first opening for retaining said thermometer in said sample holder,and a second opening having fitted therein a guide means cooperatingwith the shank portion of said stirrer elements.

4. Apparatus in accordance with claim 3 in which said sample holdercomprises a test tube coaxially disposed an outer jacket to provide anenclosed volume surrounding the walls of said test tube, the coaxialrelationship between said tube and jacket being maintained by atransverse Wall integrally connected to the lips of said tube and saidjacket and an inlet means, and an outlet means, mounted in the Wall ofsaid jacket whereby a fluid heat transfer medium can be circulatedthrough said enclosed volume. v i

5. For determining the aniline point of petroleum products, an apparatuswhich comprises an upright standard, an electrical motor mounted on saidstandard, an eccentric cam operably supported by said standard anddriven by said motor, a cross-arm reciprocatively mounted on saidstandard, said cross-arm having a guide-rod transversely attachedthereto, and a longitudinal groove registering with said cam, guidemeans mounted on said standard and slidably engaging said guide-rod tomaintain a uniform, straight-line, reciprocative motion for saidcross-arm, a plurality of sample holders each comprising a jacketed testtube having an inlet means and an outlet means in the jacket section,means for clamping said sample holders to said standard, a stirrerelement fitted in each of said sample holders, each of said stirrerscomprising a shank and a reciprocable agitator means attached to thatend of the shank disposed within said sample holder, the other end ofsaid shank being affixed to said reciprocatively mounted cross-arm, thelongitudinal axis of said sample holders and the reciprocative path ofthe stirrer elements disposed therein being substantially coextensive, athermometer disposed in said sample holder, and a closure means for saidsample holder, said closure means having a first opening for retainingsaid thermometer in said sample holder, and a second opening havingfitted therein a guide means cooperating With the shank portion of saidstirrer element.

References Cited in the file of this patent UNITED STATES PATENTS 63,515Hawk Apr. 2, 1867 1,443,537 Hortvet Jan. 30, 1923 2,068,976 Dillon Jan.27, 1937 2,252,750 Basch Aug. 19, 1941 2,349,482 Welty May 23, 19442,437,194 Harrington Mar. 2, 1948 2,604,392 Brown July 22, 1952 OTHERREFERENCES Standard Methods of Testing Petroleum and its Products, page23, method A, 1955,

